Abstract

The rhizobia, Sinorhizobium meliloti and Rhizobium sullae, which fix nitrogen in root nodules of alfalfa (Medicago sativa L.) and sulla (Hedysarum sp.) forage legumes, respectively, were isolated from root nodules and soils from Morocco. We used three PCR-based techniques namely, rep-PCR, RAPD and ARDRA techniques for genotypic characterization of 10 isolates of S. meliloti and R. sullae, in order to identify rapid and reliable techniques for applications in population genetic analysis of these species. The analysis revealed characteristic banding patterns for S. meliloti and R. sullae isolates by all the three techniques, even though the isolates are from a narrow geographic region in Morocco. Furthermore, the results showed that the rep-PCR with REP and ERIC primers was more efficient than RAPD and ARDRA technique for genotyping S. meliloti isolates; and rep-PCR with REP primers and the ARDRA technique with restriction enzyme HinfI, were more efficient than the other rep-PCR and RAPD-PCR techniques for genotyping R. sullae isolates.

Key words: Sinorhizobium meliloti, Rhizobium sullae, rep-PCR, ARDRA, RAPD, genetic diversity.